Turbocharged and supercharged engines may be configured to compress ambient air entering the engine in order to increase power. Compression of the air may cause an increase in air temperature, thus, a charge air cooler may be utilized to cool the heated air thereby increasing its density and further increasing the potential power of the engine. Ambient air from outside the vehicle travels across the CAC to cool intake air passing through the inside of the CAC. Condensate may form in the CAC when the ambient air temperature decreases, or during humid or rainy weather conditions, where the intake air is cooled below the water dew point. Condensate may collect at the bottom of the CAC, or in the internal passages, and cooling turbulators. When torque is increased, such as during acceleration, increased mass air flow may strip the condensate from the CAC, drawing it into the engine and increasing the likelihood of engine misfire.
Other attempts to address engine misfire due to condensate ingestion involve avoiding condensate build-up. However, the inventors herein have recognized potential issues with such methods. Specifically, while some methods may reduce or slow condensate formation in the CAC, condensate may still build up over time. If this build-up cannot be stopped, ingestion of the condensate during acceleration may cause engine misfire. Another method to prevent engine misfire due to condensate ingestion includes trapping and/or draining the condensate from the CAC. While this may reduce condensate levels in the CAC, condensate is moved to an alternate location or reservoir, which may be subject to other condensate problems such as freezing and corrosion.
In one example, the issues described above may be addressed by a method for periodically purging the condensate from the CAC during safe vehicle operating conditions. A CAC clean-out cycle may be initiated in response to a condensate level if operating requirements for stable combustion are fulfilled. By increasing airflow through the CAC, controlled amounts of condensate may be blown off into the engine without causing misfire. The increase in engine airflow may be counteracted by adjusting various engine actuators to maintain torque demand. In this way, the clean-out cycle may not alert the vehicle operator. By performing this clean-out routine, condensate levels in the CAC may be maintained at a low level to prevent engine misfire during normal vehicle operation.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.